Empoleon sucks, because quite frankly Infernape destroys it immediately with a STAB Life Orb'd In-Fight. Infernape needs some SpAtk EVs I believe to defeat Torterra with either Flamethrower or Fire Blast. Empoleon fails to be good in this generation, because if a Torterra can switch out then switch in and predict a Empoleon coming he can EQ for the kill
[EDIT]: Exactly what the AP said, but more in-depth kinda. And as for what Frost Nova said, Torterra is not neccesarily better than Infernape, because it is slower, giving it a disadvantage. If you want a alternative to Empoleon, Swampert works quite well